Normal Operation
Voltage is supplied to the rain sensor when the ignition is ON. The rain sensor sends data to the wiper/washer module on a dedicated circuit. When the multifunction switch is in one of the 5 auto/intermittent settings, the rain sensitive wipers activate.
The rain sensor optically senses water on the windshield. An infrared beam lights a section of the windshield. The intensity of the reflected beam is measured and compared to the intensity of the transmitted beam. When there is water on the surface of the windshield, the beam distorts, reducing the intensity of the beam. When the beam is not reflected completely, it is interpreted as rain on the windshield and the windshield wipers activate based on the sensitivity setting.
If a fault is detected with the rain sensor input by the wiper/washer module, the wiper/washer module switches to a default intermittent mode. The timing of the wipers correspond to a standard intermittent setting based on the selection on the multifunction switch.
A gel-type lens is used as the interface between the rain sensor and the windshield. If the lens is missing or damaged, the rain sensing wipers may be inoperative. If the rain sensitive wipers are inoperative and do not default to the intermittent mode, inspect the rain sensor and confirm that the gel-type lens over the rain sensor is undamaged.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Wiper blades
- Rain sensor mounting bracket not secured to the windshield
- Rain sensor gel-type lens
- Rain sensor
- Foreign material on windshield, such as dirt, dust or bugs
- Damaged windshield
- Wiper motor
- Wiper/washer module
- SJB